Google's Project Fi wireless service is official, but it's invite-only and requires a Nexus 6

Google has officially taken the wraps off its much anticipated wireless service, dubbed Project Fi. As expected, the company is essentially actings as an MVNO, providing cellular connectivity using infrastructure from carrier partners, but throwing in its own set of innovations and straightforward pricing scheme.

Both Sprint and T-Mobile are partnering with Google for the new service but you won’t have to choose between one or the other. Instead, Project Fi uses new technology to intelligently connect you to the fastest network available as you move around, so you get 4G LTE in more places.

The service also works with more than a million free, open Wi-Fi hotspots that Google has verified as fast and reliable as well as your own trusted networks. Whenever you're connected to Wi-Fi, Project Fi will use that to deliver your calls and texts, and if you walk away it will seamlessly transition to cell networks. Google promises to secure your traffic when on Wi-Fi using data encryption.

Another nice feature is the ability to connect any device that supports Google Hangouts (Android, iOS, Windows, Mac, or Chromebook) to your number, and then use that to call and text anyone.

As for pricing, Google has a single plan, which costs $20 a month for unlimited domestic talk and text, unlimited international texts, Wi-Fi tethering, and low-cost international calls in more than 100 countries. Then on top of that you pay $10 per GB for data with a minimum of 1GB per month. The twist here, as revealed a few days ago, is that you only pay for the data you use, down to the penny. Anything that goes unused is credited on your next bill.

It’s worth noting that your data allowance will cost the same in 120+ countries so you can roam without worries. It’ll be limited to 3G speeds, though.

Other consumer friendly features include a Project Fi app that offers live support around the clock, and the ability to make changes your plan any time, review and pay your bill, and check your data usage for the ongoing month.

Lastly, there are some caveats of course. For one thing, although Project Fi appears to have decent nationwide coverage, Google is rolling out an Early Access Program by invitation-only. And since Project Fi requires specific hardware to support its network switching technology, for now it is only available on the Nexus 6. Those interested can request an invite here.